Today, upon the manufacture of semiconductor laser etc., MO-CVD technique using organometallic compounds for raising the efficiency thereby is known well.
MO-CVD is to supply certain organometallic compound as a gas onto the wafer being at high temperature utilizing inert gas and to allow this gas to react on the wafer to deposit a thin film of single crystal of compound produced through this reaction.
In more detail, it is a method wherein, for example, gases of (CH.sub.3).sub.3 Ga and AsH.sub.3 are allowed to react on the wafer being at high temperature and thin film of single crystal of GaAs is deposited according to the reaction formula below: EQU (CH.sub.3).sub.3 Ga+AsH.sub.3 .fwdarw.GaAs+3CH.sub.4
In previous Japanese Patent Application No. Sho 60-219,680 (Japanese Unexamined Patent Publication No. Sho 62-83,400), the inventors made the invention that, in the cylinder for MO-CVD, a porous distributor with a pore size of 1 to 100.mu. (hereinafter referred to as filter) was fitted to the lower end of the introducing tube for inert gas thereof (hereinafter referred to as dip tube).
In the case of liquid EGMA, extremely excellent result can be obtained by putting this invention into practice. However, in the cases of solid trimethylindium (referred to as TMIn), cyclopentadienylmagnesium (referred to as Cp.sub.2 Mg) as a dopant and Cu-based EGMA, it was made clear that they were in solid form and the gases thereof were not ejected uniformly by conventional way resulting in the incapability of deposition of single crystal being uniform in composition.
There, as a result of extensive investigations, the inventors have found that, if utilizing such cylinder that the inside diameter of lower portion of cylinder is narrowed compared with the upper portion and a slant portion is provided at the upside of narrow-diameter portion, as shown in FIG. 1, excellent results can be obtained.